Plowing, of course, has been widely practiced in the agricultural arts for many decades. However, even the deepest agricultural plowing, which is normally done by a moldboard plow, seldom works the soil to a depth greater than 14 inches. Moreover, a moldboard plow is designed to lift the soil and turn it over into a previously formed furrow.
One early attempt at deep plowing of compacted soil was to pull a shank like a rock-ripper with a narrow tooth like a chisel through the soil. Such shanks have the strength to withstand deep plowing, but they simply form slots which does not promote water retention nor loosen the soil for root growth. In fact, the soil is further compacted on the upper walls of the slot formed by a ripper shank.
Another attempt was the slip plow. The slip plow consists of a vertical ripper shank with a plate 10"-15" wide and 10 ft. long attached to the lower rear portion of the shank. The rear portion of the plate is supported by a chain attached to the top of the ripper shank. The plate is pivotally attached to the shank with a horizontal pin, and the chain can be shortened or lengthened to adjust the height of the rear end. As soil flows by the ripper shank it is lifted by the upward slope of the plate. The disadvantage to the slip plow is that it generally plows a narrow bottom V-groove in the soil.
Another deep plow is a large moldboard plow with a shortened moldboard to avoid turning the soil over completely. A large landside is needed to offset the large side draft. This large landside causes considerable drag on the plow, producing heat through friction. Also, substantial side soil movement occurs leaving a large surface furrow when finishing each plowed land. Another deep chisel plow is a vertical ripper shank with relatively small triangular shaped wing. This shank has one, forward, smaller shank mounted on each side operating at a shallow depth. A similar V fracture line of that of the slip plow is accomplished with a claimed reduction in draft.